This invention relates to bags for containing liquids and to the manufacture of such bags.
Bags such as urostomy bags, urine bags, colostomy bags, etc. are commonly made from two superposed sheets of plastics material welded around their periphery. It is often desired to have an outlet tube from a lower region of the bag. Such tubes are often also plastics material. Problems arise when making weld joints to fix the tube to the two bag walls in a leak-proof manner. In particular, there frequently exist two leak paths LP at the locations indicated in FIG. 2 of the accompanying drawings. This problem is particularly acute with bags for containing urine because urine has a low surface tension and will readily find any leak path. Welding a plastics tube between bag walls is a particularly difficult problem when one is employing multi-film laminate material for each bag wall, some of the layers of the laminate being intended to provide strength and liquid permeability and one or more other layers of the laminate being particularly directed to providing gas impermeability. As will be understood, with a thin multi-laminate bag wall, joining such a wall to a tube of appreciable wall thickness presents difficulties in delivering a suitable amount of heat both to the thin bag wall film and to the relatively thick tube wall.
This invention aims to provide a bag for containing liquids in which leakage is avoided or at least substantially reduced compared to the conventional bags of the type described above.